Telegraph



2 Sheets-Sheet 1'.

(No Model.)

T. A. EDISON. TELEGRAPH. No. 448,779. Patented Mar. 24,1891.

(No Model.) M 2 Sheets-Sheet 2.

- v T. A. EDISON.

TELEGRAPH. No. 448,779. Patented Mar. 24, 1891.

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THOMAS A. EDISON, OF ILLEWELLYN PARK, NEW JERSEY.

TELEGRAPH.

SPECIFICATION forming part of Letters Patent N 0. 448,779, dated March 24, 1891.

Application filed July 19, 1886.

T0 (LZZ whom, it may concern:

Be it known that I, Tnonas A. EDISON, of Llewellyn Park, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Telegraphs, (Case No. 673,) of which the following is a specification.

The object I have in View is to utilize for telegraphic purposes two or more ordinary telegraph-lines provided with the usual Morse instruments in such manner that parts or all of these two or more lines will form an independent circuit for the transmission and reception of telegraphic signals, while the lines will separately be operated in the ordinary manner withoutinterference of signals. This enables me to connect crossing orintersectin g lines and thus establish direct communication between points at present reached by indirect telegraphic routes, requiring the transference of messages from one line to another at one or more points and causing the delay arising from this necessity. Many other convenient and desirable arrangements of circuits are also made possible by the invention.

I employ the induction telegraphic apparatus for transmitting and receiving the extra set of signals, the principle of which apparatus is covered by my Patent N 0.833389.

The signals are composed of induction-im pulses produced by a key from a special source of electrical energy and received by diaphragm receivers 0r sounders. The regular Morse signaling-keys and relays are shunted by condensers to keep the line constantly closed for the induction-i111pulses.

In carrying out my invention the two or more separate Morse lines are connected by .condensers or induction-coils, and, where necessary to properly direct the induction-impulses, retarding or damming magnets are inserted in the lines.

In the accompanying drawings, forming a part hereof, Figure 1 illustrates by diagram the connection of crossing Morse lines midway of the length of each. Fig. 2 is a similar view of lines, one of which is connected at its end to the center of the other line. Fig. 3 is asimilar view of the connection of a through line and a way line to reach an oflice in a loop from the way line, and Fig. 4 a view showing the use of an induction-coil for connecting two lines. Other differences between Serial No. 208.359. (No model.)

the figures of the drawings will be specifically pointed out in the description.

In Fig. 1 lines L L and L L cross near their centers. For simplicity each line is represented with only two telegraph-offices, those of the line L L being designated by A and I3 and thoseot' the line L L by C and D. These lines are each grounded at their ends and have the usual line-batteries m I). At each ofiice is the ordinary Morse telegraph set, composed of signalingkey a, relay Z), and a sounder. (Not shown.) The key a and relay b at each oliiee are shunted by a condenser 0. At each office is also an induction telegraph set,which isiilustrated as composed of magnetic coil (1, located in the line and shunted by a local battery Z Z) through the lever and points of a sounder e, controlled by a transmitting-key f, and a diaphragm receiver 9, also in the line. The lines L L and L L are connected together by a condenser E, joining the two lines into a common induction-circuit, while the lines remain independent l'or telegraphing by the ordinary Morse instruments. If it is desired to cut oft an oflice (say B) from the induction-circuit, a retarding or damming magnet F will be introduced in the line L L between such o'ffice and the point of the connection with the line of the condenser E. A switch It can be provided for cutting out this magnet, so as to restore the oftlce cutout to the induction-circuit. It will be seen that by the use of retarding or damming magnets and switches and lines connected by condensers many different arrangements may be made of the induction-circuits without interfering with the use of the lines separately for the regular Morse telegraphing.

In Fig. 2 line L L is connected at its center by a condenser E with the end of a line L L extendingoff in another direction. The line L L has ofiices G H, the first having an ordinary Morse set and an induction set, and the second only an ordinary Morse set without a condenser around the key and relay. In line L L between office II and the condenser E is a retarding or damming magnet F. By omitting this magnet or providing a switch to cut it out of circuit the oilice II could also be made an induction office, as is the ofiice'B on line L L in Fig. 1. The line l. J." has two oti'iees I K. The ollice l, which lines for induction-signals the principle of is near the inner end of the line, has only an current or magnetic induction may be emordinary Morse set with a shunted key and relay; but it may also have an induction set. The oiiice K has both an ordinary Morse set and an induction set. Between the condenser E and the ground at that endof the line this line L I. is provided with a retarding or damming magnet l to force the il'iduetion-signals i to seek ground at the farther end of the line through the instruments at oi'h'ee K.

In Fig. 3 for simplicity the ordinary Morse sets are designated by circles M and M and the induction sets by squares l.

The Morse sets of circles M have shunted keys and relays, while those of circles M need not be shunted. The line L L is a through line between stations N and 0, while the line L L is a way line between such stations, and also has a. lateral 1001) including an oilice (Q. It is desired to use the through line I. L for an induction-circuit between the stations N and 0, so as to avoid the resistance of the instruments at the way ofticcs on line If if and to obviate the expenses of shunting by condensers the keys and relays at such way otfiees, and it is also desired to include the Office Q in theinduction-circuit. The object stated is accomplished completely by conneetingthe sides of the loop from the wayline If If, leading to station Q, with the through line l; I. by condensers E" and E and by locating in the line L L' between such condenserconneetions a retarding or dan'nning magnet The induction-circuit will thus be established from ground at the station N over line L L to condenser E by loop of line If If to station Q, back by loop and through condenser E to line L" L", and thence to ground at the station 0.

It is evident that instead of employing the principle of static induction to connect the ployed, as by the use of an induction-coil R, Fig. 4., one line being connected with one cir- Quit of the coil and the other line with the second circuit. The induction-coil preferably has an iron core, and may, for example, be of one hundred ohms resistance in each circuit.

hat I claim is l. The combination, with two or more telegraph-lines, each having ordinary Morse sets and induction sets, of one or moreinductionconnections between such lines and one or more retarding or damming magnets to divert the induction-signals from portions of such lines, substantially as set forth.

The combination,with two or more telegraph-lines, each having ordinary Morse sets and induction sets, of one or more inductionconnections between such lines, one or more retarding or dannning magnets to divert the induction-signals from portions of suchlincs, and one or more switches for modifying the effect of such retarding or dainming magnet. or magnets, substantially as set forth.

3. The combination of a telegraph-line provided at two or more points with signalinglceys and receivers and provided also at. one or more points with induction sets in series with said keys and receivers, a branch or crossing line provided with similar instruments, said lines being inductivelyconnected, a retarding-magnet in the first line, and a retarding-magnet in the branch or crossing line, substantially as set forth.

This specification signed and witnessed this th day of July, 1886.

TliOS. A. EDISON.

Witnesses:

WM. PELZER, E. t. ROWLAND. 

